Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
1.
Food Funct ; 14(6): 2597-2606, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36847183

RESUMO

Eggs contain high-quality protein, lavish vitamins and other bioactive nutrients but are rich in cholesterol. Our study is designed to assess the association of egg intake with polyp prevalence. A total of 7068 participants at a high risk of CRC from the Lanxi Pre-Colorectal Cancer Cohort Study (LP3C) were recruited. A food frequency questionnaire (FFQ) was utilized to obtain dietary data through a face-to-face interview. Cases of colorectal polyps were identified by electronic colonoscopy. The logistic regression model was exploited to achieve odds ratios (ORs) and 95% confidence intervals (CIs). Overall 2064 cases of colorectal polyps were identified in the 2018-2019 survey of LP3C. A positive association of egg consumption with colorectal polyp prevalence was found after the multivariable adjustment [ORQ4 vs. Q1 (95% CI): 1.23 (1.05-1.44); Ptrend = 0.01]. However, a positive relationship disappeared after further adjustment for dietary cholesterol (Ptrend = 0.37), which explained that the harmful role of eggs could be ascribed to the high content of dietary cholesterol. Besides, a positive trend was found between dietary cholesterol and polyp prevalence [OR (95% CI): 1.21 (0.99-1.47); Ptrend = 0.04]. Furthermore, replacing 1 egg (50 g d-1) with an equal amount of total dairy products was related to 11% lower colorectal polyp prevalence [OR (95% CI): 0.89 (0.80-0.99); P = 0.03]. In summary, higher egg consumption was correlated with a higher polyp prevalence among the Chinese population at a high risk of CRC, which was ascribed to the high content of dietary cholesterol in eggs. Besides, individuals with the highest dietary cholesterol tended to have a higher polyp prevalence. Reducing the consumption of eggs and replacing eggs with total dairy products as alternative protein sources may prevent the occurrence of polyps in China.


Assuntos
Pólipos do Colo , Neoplasias Colorretais , Humanos , Pólipos do Colo/epidemiologia , Fatores de Risco , Colesterol na Dieta , Estudos de Coortes , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/prevenção & controle , Dieta
2.
Nanoscale ; 14(40): 14984-14996, 2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36193714

RESUMO

Nitric oxide is critical for eliminating infection and promoting regeneration in diabetic wounds. However, clinical uses of nitric oxide are limited by its high activity and lack of specificity in targeting infections. Herein, we develop an intelligent nitric oxide nanogenerator comprising isosorbide dinitrate (ISDN)-coated copper sulfide (CuS)/calcium carbonate (CaCO3) core/shell nanoparticles (CuS@CaCO3-ISDN) to target the acidic microenvironment of the infected diabetic wounds. Meaningfully, triggered by acid decomposition of CaCO3, this nanogenerator can achieve a responsive and accelerated release of nitric oxide from ISDN through enzyme-mimicking redox processes that involve CuS nanoparticles and then inactivate biofilm bacteria through the pathways of oxidative stress and disruption of adenosine triphosphate (ATP)-related energy metabolism. Moreover, after eliminating the infection, the pH-responsive release of nitric oxide can promote the proliferation of blood vessels and tissue regeneration and accelerate diabetic wound closure. This study expands the use of nitric oxide donors in wound treatment by developing the enzyme-mimicking release strategy, and the pH-responsive core/shell nanogenerator is promising for a variety of anti-infection therapeutic applications.


Assuntos
Diabetes Mellitus , Doadores de Óxido Nítrico , Humanos , Óxido Nítrico/metabolismo , Cobre , Dinitrato de Isossorbida , Trifosfato de Adenosina/metabolismo , Concentração de Íons de Hidrogênio , Carbonato de Cálcio , Sulfetos
3.
Int J Mol Sci ; 22(21)2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34769361

RESUMO

In the present study, four large-scale field trials using two doubled haploid wheat populations were conducted in different environments for two years. Grain protein content (GPC) and 21 other yield-related traits were investigated. A total of 227 QTL were mapped on 18 chromosomes, which formed 35 QTL clusters. The potential candidate genes underlying the QTL clusters were suggested. Furthermore, adding to the significant correlations between yield and its related traits, correlation variations were clearly shown within the QTL clusters. The QTL clusters with consistently positive correlations were suggested to be directly utilized in wheat breeding, including 1B.2, 2A.2, 2B (4.9-16.5 Mb), 2B.3, 3B (68.9-214.5 Mb), 4A.2, 4B.2, 4D, 5A.1, 5A.2, 5B.1, and 5D. The QTL clusters with negative alignments between traits may also have potential value for yield or GPC improvement in specific environments, including 1A.1, 2B.1, 1B.3, 5A.3, 5B.2 (612.1-613.6 Mb), 7A.1, 7A.2, 7B.1, and 7B.2. One GPC QTL (5B.2: 671.3-672.9 Mb) contributed by cultivar Spitfire was positively associated with nitrogen use efficiency or grain protein yield and is highly recommended for breeding use. Another GPC QTL without negatively pleiotropic effects on 2A (50.0-56.3 Mb), 2D, 4D, and 6B is suggested for quality wheat breeding.


Assuntos
Cromossomos de Plantas/genética , Ligação Genética , Melhoramento Vegetal , Proteínas de Plantas/genética , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Triticum/genética , Mapeamento Cromossômico , Fenótipo , Triticum/classificação
5.
Plant Biotechnol J ; 19(12): 2662-2672, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34448351

RESUMO

Moderately rolled leaf is one of the target traits of the ideal plant architecture in rice breeding. Many genes, including homeodomain leucine zipper IV transcription factors ROC5 and ROC8, regulating rice leaf rolling have been cloned and functionally analysed. However, the molecular mechanism by which these genes modulate leaf-rolling remains largely elusive. In this study, we demonstrated the transcription activation activity of both ROC8 and ROC5. Overexpressing ROC8 caused adaxially rolled leaves due to decreased number and size of bulliform cells, whereas knockout of ROC8 induced abaxially rolled leaves due to increased number and size of bulliform cells. ROC8 and ROC5 each could form homodimer, but ROC8 interacted preferably with ROC5 to forms a heterodimer. Importantly, we showed that the ROC8-ROC5 heterodimer rather than the homodimer of ROC8 or ROC5 was functional as neither overexpressing ROC8 in the ROC5 mutant nor overexpressing ROC5 in the ROC8-knockout line could rescue the mutant phenotype. This was further partially supported by the identification of a large number of common differentially expressed genes in single and double mutants of roc8 and roc5. ROC8 and ROC5 were functionally additive as the phenotype of abaxially rolled leaves was stronger in the roc5roc8 double mutant than in their single mutants. Our results provide evidence for the role of dimerization of ROC members in regulating leaf rolling of rice.


Assuntos
Oryza , Regulação da Expressão Gênica de Plantas/genética , Oryza/fisiologia , Fenótipo , Melhoramento Vegetal , Folhas de Planta , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética
6.
ACS Appl Mater Interfaces ; 13(16): 18443-18453, 2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33848120

RESUMO

Nonhealing wounds have become a major healthcare burden worldwide. Chronic wound healing is universally hampered by the presence of bacterial infections that form biofilms. Therefore, in this study, a novel nanoliquid dressing based on a mild photothermal heating strategy was designed to provide safe healing of biofilm-infected wounds. Dilute nitric acid (HNO3) solution was employed to induce a redox process triggered by copper sulfide (CuS) nanoplates in the nanoliquid dressing. This redox process was further promoted by the mild photothermal effect (≤47.5 °C) that generated a sufficient amount of reactive oxygen species, resulting in less thermal injury to normal tissues. Correspondingly, with the safe concentration of CuS nanoplates (0.4 mg/mL), excellent bactericidal efficiencies up to 98.3 and 99.3% against ampicillin-resistant Escherichia coli (Ampr E. coli) and Staphylococcus aureus (S. aureus) were achieved, respectively. Moreover, the nanoliquid dressing exhibited a near-infrared enhanced destructive effect on mature biofilms. According to in vivo wound healing experiments in mice, the nanoliquid dressing increased the healing rate and reduced the inflammatory response. This study provides a novel insight into treating the biofilm-infected chronic wounds in the "post-antibiotic era".


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Bandagens/microbiologia , Nanomedicina/métodos , Terapia Fototérmica , Cicatrização/efeitos dos fármacos , Animais , Cobre/química , Cobre/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Camundongos , Oxirredução , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Sulfetos/química , Sulfetos/farmacologia
7.
Rev Sci Instrum ; 92(3): 033308, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33820000

RESUMO

With the development of the precise radiotherapy, the accuracy of radiotherapy equipment is gradually improved. The gantry, the carrier of the treatment head and various testing devices, is the most important component that determines the accuracy of the entire equipment. In this paper, the layout of the O-ring linear accelerator and the structure of the gantry are optimized to reduce the weight of the gantry by 50% and the moment of inertia by 60%. A mechanical isocenter detection method based on the laser tracker is proposed to conduct a rapid and accurate isocenter measurement for the optimized gantry. The experimental results show that the maximum deformation of the optimized gantry under load is 0.13 mm during rotation and the maximum intersection distance between the gantry axis and the treatment head axis at the isocenter position is 0.21 mm.

9.
Rice (N Y) ; 13(1): 76, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33169285

RESUMO

Heterotrimeric GTP binding proteins (G proteins) and cytokinin play important roles in regulating plant growth and development. However, little is known about the mechanism by which they coordinate the regulation of grain size in rice. We functionally characterized one gene, RGG1, encoding a type-A Gγ subunit. Strong GUS staining was detected in young panicles and spikelets, suggesting a role for this gene in modulating panicle-related trait development. Overexpression of RGG1 in Nipponbare (NIP) and Wuyunjing 30 (WYJ30) significantly decreased plant height, panicle length and grain length by regulating cell division. However, rgg1 mutants generated by the CRISPR/Cas9 system exhibited no obvious phenotypic differences, which may be due to the extremely low expression level of this gene in vivo. The transcriptomes of young panicles of NIP, the NIP-rgg1-2 mutant and the NIP-OE2 overexpression line were sequenced, and the results showed that many differentially expressed genes (DEGs) were associated with the cytokinin biosynthetic pathway. We confirmed this result by measuring the endogenous cytokinin levels and found that cytokinin content was lower in the overexpression lines. Additionally, increased expression of RGG1 decreased sensitivity to low concentrations of 6-benzylaminopurine (6-BA). Our results reveal a novel G protein-cytokinin module controlling grain size in rice and will be beneficial for understanding the mechanisms by which G proteins regulate grain size and plant development.

10.
Exp Ther Med ; 20(2): 1003-1011, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32765656

RESUMO

Drug-induced cardiomyopathy is a severe disease that leads to refractory heart disease at late stages, with increasing detrimental effects. DOX-induced cell damage is primarily induced via cellular oxidative stress. The present study investigated the effects of catalpol on doxorubicin (DOX)-induced H9C2 cardiomyocyte inflammation and oxidative stress. The Cell Counting Kit-8 assay was performed to detect cell viability, and western blotting was performed to detect the expression of peroxisome proliferator-activated receptor (PPAR)-γ in H9C2 cells. The expression levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß and IL-6 were measured using ELISAs. Furthermore, the oxidative stress kit was used to detect the levels of malondialdehyde, superoxide dismutase and glutathione peroxidase. A reactive oxygen species (ROS) kit and DCF-DA staining were used to detect ROS levels. The results indicated that DOX treatment inhibited H9C2 cell expression of PPAR-γ and decreased H9C2 cell viability. Various concentrations of catalpol exhibited a less potent effect on H9C2 cell viability compared with DOX; however, catalpol increased the viability of DOX-induced H9C2 cells. Catalpol treatment also significantly decreased the expression levels of inflammatory factors (TNF-α, IL-1ß and IL-6) in DOX-induced H9C2 cells, which was reversed by transfections with short hairpin RNA targeting PPAR-γ. Results from the present study indicated that catalpol ameliorated DOX-induced inflammation and oxidative stress in H9C2 cardiomyoblasts by activating PPAR-γ.

12.
Parasitol Res ; 118(6): 1833-1840, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30989329

RESUMO

The present study assessed the prevalence and morphology of Leucocytozoon podargii from wild tawny frogmouths (Podargus strigoides) in Western Australia (WA) and genetically characterised the cytochrome b gene (cyt b) of L. podargii in wild tawny frogmouths from WA and Queensland (QLD). The prevalence of L. podargii in wild tawny frogmouths from WA was 93.3% (14/15; 95% CI, 68.1-99.8%). The morphological characters of L. podargii from WA were similar to L. podargii from QLD: the gametocytes were round-oval shape, approximately 8-12 µm in diameter; the macrogametocytes were 12.4 µm in diameter; microgametocytes were 10.4 µm in diameter; and the ratio of macrogametocytes and microgametocytes was 3:2. Sequence analysis of partial cyt b gene fragments revealed that L. podargii sequences isolated from wild tawny frogmouths in WA shared the highest similarity (99.8% at nucleotide level and 100% at protein level) with L. podargii isolated from wild tawny frogmouths in QLD. The mitochondrial 18S rRNA gene of L. podargii gametocytes was quantified using droplet digital PCR (ddPCR), and the highest gametocyte load was detected in the lung. This finding corresponds to the results of the histological study. Based on the morphological and molecular studies, it was concluded that the Leucocytozoon parasite identified from wild tawny frogmouths in WA is consistent with L. podargii from wild tawny frogmouths in QLD, and the present study has genetically characterised two different L. podargii genotypes (QLD and WA) for the first time.


Assuntos
Aves/parasitologia , Citocromos b/genética , Haemosporida/classificação , Haemosporida/genética , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologia , Animais , DNA de Protozoário/genética , Genótipo , Filogenia , Queensland/epidemiologia , RNA Ribossômico 18S/genética , Austrália Ocidental/epidemiologia
13.
PLoS One ; 13(10): e0205562, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30304037

RESUMO

Aerobic exercise improves cognitive function and adult hippocampal neurogenesis. However, the effects of aerobic exercise combined with strength exercise on cognitive function and adult hippocampal neurogenesis are still unknown. In this study, we established exercise paradigms in rats to mimic aerobic exercise combined with low- and high-intensity strength exercise. We found that aerobic exercise improved spatial learning and memory as well as adult hippocampal neurogenesis, whereas strength exercise suppressed aerobic exercise-induced cognitive improvements and adult hippocampal neurogenesis in an intensity-dependent manner. Furthermore, the levels of ß-hydroxybutyrate (ß-HB) and its downstream effector brain-derived neurotrophic factor (BDNF) were increased in the aerobic exercise group, and strength exercise impaired the aerobic exercise-induced increases in ß-HB and BDNF mRNA levels. Taken together, these results demonstrated that strength exercise weakened aerobic exercise-induced cognitive improvements and adult hippocampal neurogenesis in rats.


Assuntos
Cognição/fisiologia , Treinamento Resistido , Corrida/fisiologia , Corrida/psicologia , Ácido 3-Hidroxibutírico/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Hipocampo/fisiologia , Masculino , Aprendizagem em Labirinto/fisiologia , Modelos Animais , Neurogênese/fisiologia , RNA Mensageiro/metabolismo , Distribuição Aleatória , Ratos Wistar , Comportamento Sedentário , Memória Espacial/fisiologia
14.
Stem Cell Res Ther ; 8(1): 18, 2017 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-28129792

RESUMO

BACKGROUND: Stem cells provide a promising candidate for the treatment of the fatal pediatric dilated cardiomyopathy (DCM). This study aimed to investigate the effects of intramuscular injection of human umbilical cord-derived mesenchymal stem cells (hUCMSCs) on the cardiac function of a DCM rat model. METHODS: A DCM model was established by intraperitoneal injections of doxorubicin in Sprague-Dawley rats. hUCMSCs at different concentrations or cultured medium were injected via limb skeletal muscles, with blank medium injected as the control. The rats were monitored for 4 weeks, meanwhile BNP, cTNI, VEGF, HGF, GM-CSF, and LIF in the peripheral blood were examined by ELISA, and cardiac function was monitored by echocardiography (Echo-CG). Finally, the expression of IGF-1, HGF, and VEGF in the myocardium was examined by histoimmunochemistry and real-time PCR, and the ultrastructure of the myocardium was examined by electron microscopy. RESULTS: Injection of hUCMSCs markedly improved cardiac function in the DCM rats by significantly elevating left ventricular ejection fraction (LVEF) and left ventricular fraction shortening (LVFS). The BNP and cTNI levels in the peripheral blood were reduced by hUCMSCs, while HGF, LIF, GM-CSF, and VEGF were increased by hUCMSCs. Expression of IGF-1, HGF, and VEGF in the myocardium from the DCM rats was significantly increased by hUCMSC injection. Furthermore, hUCMSCs protected the ultrastructure of cardiomyocytes by attenuating mitochondrial swelling and maintaining sarcolemma integrity. CONCLUSIONS: Intramuscular injection of UCMSCs can improve DCM-induced cardiac function impairment and protect the myocardium. These effects may be mediated by regulation of relevant cytokines in serum and the myocardium.


Assuntos
Cardiomiopatia Dilatada/terapia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/metabolismo , Recuperação de Função Fisiológica/fisiologia , Volume Sistólico/fisiologia , Função Ventricular Esquerda/fisiologia , Animais , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/metabolismo , Cardiomiopatia Dilatada/patologia , Sangue Fetal/citologia , Sangue Fetal/metabolismo , Regulação da Expressão Gênica , Fator Estimulador de Colônias de Granulócitos e Macrófagos/sangue , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator de Crescimento de Hepatócito/sangue , Fator de Crescimento de Hepatócito/genética , Humanos , Injeções Intramusculares , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Fator Inibidor de Leucemia/sangue , Fator Inibidor de Leucemia/genética , Masculino , Células-Tronco Mesenquimais/citologia , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Cardíacas/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Peptídeo Natriurético Encefálico/sangue , Peptídeo Natriurético Encefálico/genética , Ratos , Ratos Sprague-Dawley , Transplante Heterólogo , Troponina I/sangue , Troponina I/genética , Fator A de Crescimento do Endotélio Vascular/sangue , Fator A de Crescimento do Endotélio Vascular/genética
15.
Theor Appl Genet ; 125(5): 967-73, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22660629

RESUMO

Powdery mildew (PM), caused by Blumeria graminis f. sp. tritici (Bgt), has become a serious disease and caused severe yield losses in the wheat production worldwide. Resistance gene(s) in wheat cultivars can be quickly overcome by newly evolved pathogen races when these genes are employed for long time or in a large area. It is urgent to search for new sources of resistance to be used in wheat breeding. Tabasco is a German resistant cultivar and a new source of resistance gene(s) to PM. An F(2) population was developed from a cross between Tabasco and a Chinese susceptible cultivar Ningnuo 1. Infection types in 472 F(2) plants and 436 F(2-3) families were evaluated by inoculating plants with isolate Bgt19. Results showed that a single dominant gene, designed Pm46, controlled powdery mildew resistance in Tabasco. This gene was located to the short arm of chromosome 5D (5DS) and flanked by simple sequence repeat markers Xgwm205 and Xcfd81 at 18.9 cM apart. Because another resistance gene Pm2 was also located on 5DS, 15 Bgt isolates were used to inoculate Tabasco and Ulka/8*Cc (Pm2 carrier). The results showed that Tabasco was highly resistant to all of the 15 isolates tested, while Ulka/8*Cc was susceptible to 4 of the isolates, suggesting that Tabasco may carry resistant gene(s) different from Pm2 gene in Ulka/8*Cc. To test the allelism between Pm46 and Pm2, an F(2) population between Tabasco and Ulka/8*Cc was developed. Isolate Bgt2, avirulent to both parents, was used to evaluate the F(2) population and two susceptible plants were identified from 536 progenies with F(2) plants. This result indicated that Pm46 is not allelic to Pm2. Therefore, Pm46 is a new gene for PM resistance identified in this study.


Assuntos
Basidiomycota/patogenicidade , Mapeamento Cromossômico , Genes de Plantas/genética , Imunidade Inata/genética , Doenças das Plantas/genética , Locos de Características Quantitativas/genética , Triticum/genética , Triticum/microbiologia , Alelos , Basidiomycota/genética , Basidiomycota/imunologia , Cromossomos de Plantas/genética , DNA de Plantas/genética , Ligação Genética , Marcadores Genéticos , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Reação em Cadeia da Polimerase , Triticum/imunologia
16.
Plant Biotechnol J ; 10(3): 301-12, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22044435

RESUMO

Cotton (Gossypium spp.) is an important economic crop and the largest source of textile fiber in the world. However, to date, only a few genes have been identified that exhibit critical roles in fiber development, and few has shown positive effects on fiber yield and quality in transgenic cotton. Here, we report the characterization of a novel sucrose synthase (SusA1) gene from a superior quality fiber germplasm line 7235 in Gossypium hirsutum. By association analysis, GhSusA1 was highly correlated with fiber qualities in (7235× TM-1) recombinant inbred lines based on polymorphism of GhSusA1 between 7235 and TM-1. Subsequently, based on an interspecific population of 141 BC1 individuals generated from the cross between TM-1 and Gossypium barbadense line, Hai7124, we further mapped GhSusA1 genes on homeologous chromosomes A8 (chro.8) and D8 (chro.24). Suppression of GhSusA1 in transgenic cotton reduced fiber quality and decreased the boll size and seed weight. Importantly, overexpression of this gene increased fiber length and strength, with the latter indicated by the enhanced thickening of cell wall during secondary wall formation stage. Moreover, increasing GhSusA1 transcript abundance in vegetative tissues led to elevated seedling biomass. Together, these findings identified GhSusA1 as a key regulator of sink strength in cotton, which is tightly associated with productivity, and hence a promising candidate gene that can be developed to increase cotton fiber yield and quality.


Assuntos
Fibra de Algodão , Glucosiltransferases/metabolismo , Gossypium/metabolismo , Proteínas de Plantas/metabolismo , Parede Celular/genética , Parede Celular/metabolismo , Parede Celular/fisiologia , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Cromossomos de Plantas/metabolismo , Clonagem Molecular , Cruzamentos Genéticos , Evolução Molecular , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Glucosiltransferases/genética , Gossypium/genética , Gossypium/fisiologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Plântula/genética , Plântula/metabolismo , Plântula/fisiologia , Sementes/metabolismo , Sementes/fisiologia , Tetraploidia
17.
Plant Mol Biol ; 72(4-5): 397-406, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20131110

RESUMO

Cotton fiber elongation, largely achieved by cell wall loosening, is an important stage during cotton fiber development. In this present research, a fiber preferential cDNA encoding a pectate lyase (PEL) which could exclusively degrade the de-esterified pectin was isolated from a cotton (Gossypium hirsutum) fiber cDNA library. Subsequently, the corresponding PEL genes were isolated from four different cotton species and characterized. In vitro enzyme assays indicated that GhPEL really exhibited cleavage-activity against de-esterified pectin. The temporal-spatial expression analyses revealed that the GhPEL gene was preferentially expressed in fibers at 10 days-post anthesis (DPA). Antisense GhPEL transgenic cotton plants were generated by Agrobacterium-mediated transformation. Six homozygous lines, each with one or two copies of the transgene inserted as determined by southern blot analysis of the NPTII gene, were selected for further functional analysis. The GhPEL expression during fiber elongation in these transgenic lines was significantly suppressed in various degrees. Furthermore, the reduction of GhPEL enzymatic activity by decreasing GhPEL transcripts severely affected the degradation of de-esterified pectin in primary cell walls of transgenic cotton fibers, which consequently blocked cell wall loosening in early fiber development. Ultimately, the fiber elongation of all these transgenic lines was repressed. These results suggested that GhPEL may play an important role in the process of normal fiber elongation in cotton.


Assuntos
Genes de Plantas , Gossypium/enzimologia , Gossypium/genética , Polissacarídeo-Liases/genética , Polissacarídeo-Liases/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Parede Celular/metabolismo , Fibra de Algodão , DNA Complementar/genética , DNA de Plantas/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Gossypium/crescimento & desenvolvimento , Dados de Sequência Molecular , Pectinas/metabolismo , Filogenia , Plantas Geneticamente Modificadas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Especificidade da Espécie
18.
J Am Soc Mass Spectrom ; 16(1): 60-70, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15653364

RESUMO

Eleven different anionic species were able to form adducts with neutral oligosaccharides at low cone voltage in negative ion mode electrospray mass spectrometry. Among them, fluoride and acetate have the ability to significantly enhance the absolute abundance of [M - H](-) for neutral oliogosaccharides, which otherwise have low tendencies to deprotonate due to the lack of a highly acidic group. Evidence shows that the source of high abundances of [M - H](-) for neutral oligosaccharides arises from the decomposition of [M + F](-) and [M + Ac](-) with neutral losses of HF and HAc, respectively. The chloride adducts have the best stability among all the adduct species investigated, and chloride adducts consistently appeared in higher abundances relative to [M - H](-). In tandem mass spectrometry (ES-MS/MS) experiments, upon collision induced dissociation (CID), F(-) and Ac(-) adducts gave purely analyte-related product ions, i.e., no detection of the attaching anion and no incorporation of these anions into decomposition products. Cl(-) adducts produced both Cl(-) and analyte-related product ions. For the above three anions, CID of adduct species may be used for structural determination of neutral oligosaccharides because, in each case, structurally-informative fragment ions were produced. In the presence of F(-) and Ac(-), simultaneous detection of acidic and neutral oligosaccharides was achieved, because the problem of the presence of an acidic group that can impede the deprotonation of a neutral oligosaccharide was minimized. The ratio of Cl(-):non-Cl-containing product ions obtained in CID spectra of chloride adducts of disaccharides was used to differentiate anomeric configurations of disaccharides. Density functional theory (DFT) was employed to evaluate the optimized structures of chloride adducts of disaccharides, and it was found that chloride anions favor close contact with the hydrogen from the anomeric hydroxyl group. Multiple hydrogen bonding further stabilizes the chloride adduct.


Assuntos
Cloretos/química , Oligossacarídeos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Ânions/química , Configuração de Carboidratos , Estrutura Molecular
19.
Anal Chem ; 75(7): 1638-44, 2003 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-12705596

RESUMO

The formation and decomposition (postsource decay, PSD) of anionic adducts in negative ion matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry have been studied. Chloride, a small inorganic anion, has been found to form stable anionic adducts with a variety of neutral oligosaccharides that can survive the MALDI process to give readily identifiable signals (with characteristic isotope patterns) allowing subpicomole detection in the best cases. The matrixes that can aid the formation of chloride adducts of oligosaccharides have gas-phase acidities lower than or close to that of HCl (1373 kJ/mol). In PSD experiments, precursor chloride adducts of oligosaccharides yield fragment ions that retain the charge on the sugar molecule rather than solely forming Cl-, and these fragments can provide structurally informative product ions. In negative ion MALDI, highly acidic oligosaccharides do not form adducts with chloride anions, but mildly acidic saccharides (e.g., containing a carboxylic acid group) form both deprotonated molecules and chloride adducts, and each may provide structural information concerning the oligosaccharide upon decomposition.


Assuntos
Cloretos/química , Oligossacarídeos/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Ácidos , Ânions/química , Configuração de Carboidratos , Sequência de Carboidratos , Dados de Sequência Molecular , Estrutura Molecular , Sacarose/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA